Alloy



Patented Jan. 2, i934 I I UNlTED STATE S PATENT OFFICE ALLOY Robert T. Wood; Cleveland, Ohio, assignor, by mesne assignments, to Magnesium Development Corporation, a corporation of Delaware No Drawing. Application November 17, 1932 Serial No. 643,033

2 Claims. (Cl. 751) The invention relates to magnesium base alloys per square inch, a yield point of 21,000 pounds per and is directed to the development of alloys of this square inch, and an elongation of 12.0 per cent class which, while possessing the desirable charin two inches as compared with the properties acteristics of the class as a whole, are further of a similar alloy not containing aluminum which characterized by increased tensile strength and had a tensile strength of 33,000 pounds per square high yield point, as well as by a greatly increased inch, a yield point of 17,000 pounds per square elongation. inch, and an elongation of 6.5 per cent in two The use of magnesium base alloys has been inches. This comparison shows an unusual propquite seriously limited by a number of consideraerty of my alloys, which is the fact that tensile 10 tions such as difliculty of working and casting, strength and elongation are simultaneously inand inferior tensile strength as compared with creased. many of the strong aluminum alloys. It is quite When my improved alloys are used for extrugenerally appreciated that any improvement in sion purposes they may also contain zinc in 7 mangesium alloys which means increased yield amounts ranging from 0.1 per cent to 5 per cent. point, strength and elongation will be very valu-- The addition of zinc in the amounts indicated able, and for this reason efiorts have been congives superior properties to the alloy'in the extinuously expended in the search for improvetruded condition and the improvement is parment along these lines. It is to this general ticularly manifested when the zinc is present in 75 object that the present invention is directed. amounts of from 1 to 3 per cent. The addition A particular object of the invention is the of zinc is likewise generally beneficial to my immodification of magnesium base alloys containproved alloys, but if the alloys are to be forged ing tin and manganese, by the addition thereto or rolled, as distinguished from extruded, the of aluminum as a principal alloying ingredients alloys should preferably not contain over about s with or without the addition of lesser amounts of 1 per cent of zinc. zinc, to produce an alloy of increased tensile I have found that tin increases the corrosion strength, yield point and elongation. resistance of the mamesium base aluminum- I have discovered a very useful range of comzinc-manganese alloys without adversely affect-- position over which aluminum additions are 1131- ing the mechanical properties. The results of ticularly effective in producing the desired imthe tests which I have conducted indicate that. provement in tensile properties without serious the increase in corrosion resistance is quite nodetriment to the other properties of this class of ti ble whe the alloy is in the extruded condiy A rding to my invention, the, alloy y tion. While the magnesium base alloys containcontain from 0.1 to 12.0 per cent of tin, from ing tin, aluminum and manganese, with or with- 0.5 to 6.0 per cent of aluminum, and from 0.1 to o t zinc, are entirely satisfactory in achieving D cent of a ganese. The aluminum the objects and advantages hereinabove enuases the te s e strength as much as 15 pe merated, other elements may be added toproduce cent, the y eld po as much as 20 P cent. and a new property in the alloys or to affect or modify the elongation as much as 100 per cent. As a an ld property without substantially departing result of the tests which I have conducted, I have from t n ti n 50 long as t material propfound further that the magnesium alloy containti of th alloys are t substantially ing tin, aluminum and manganese is superior to air d, ma nesi mbase all y containin only alumi-. The alloys herein disclosed and claimed may n because of pr v h t-workin h r be subjected to the usual thermal treatmentsfor pa t ular y hamm r-f r n ha a r-- the purpose of improving or altering their propistics. The alloy can also be extruded. w erties.

The improvement in physical properties is par- 1 laim; ticularly marked throughout what I consider to 1, An alloy containing about 0.1 to about 12.0 be the Preferred a e of composition, which per cent of tin, about 0.5 to about 6.0 per cent of cludes alloys containing from 4.0 to 6.0 per cent aluminum, and about 0.1 to about 1.0 per cent of tin, 3.5 to 4.5 per cent of aluminum, and 0.5 of manganese, the balance being substantially to 0.8 per cent of manganese. As an example of magnesium. my preferred composition, 1 have produced an 2. An'alloy containing about 4.0 to about 6.0 alloy containing 5.6 per cent'of tin, 4.2 per "cent per cent of tin, about 3.5 to about 4.5 percent of aluminum, and 0.8 per cent of manganese. of aluminum, and about 0.5 to about 0.8 per cent 55 Tests performed on this alloy in the unheatof mangane the a ce bei g substantialLv treated and hammer-forged condition showed the magnesium. s alloy to-have a tensile'strength of 37,500 pounds ROBERT T. WOOD. 

